The use of various handheld tools is well known in the field of dentistry. One of the most common handheld dental tools is an explorer that typically consists of a metal shaft having a sharpened point at one or both ends of the shaft. U.S. Pat. Nos. 1,397.395 and 4,109,384 describe explorer-like dental tools that incorporate a flattened shank member as the working tip of the tool. In U.S. Pat. No. 1,397,395 the shank is integral to the handle, whereas in U.S. Pat. No. 4,109,384 the shank is secured in an end of the handle.
Another common handheld dental tool consists of a metal shaft having a pliable tip at one or both ends that is removable. U.S. Pat. Nos. 2,106,597 and 4,586,901 describe dental tools with removable tips where the tips are secured by a knob-like or button-like head at the distal end of the shaft. U.S. Pat. No. 532,720 describes a dental tool having a tip shaped similar to the shape of a pliable rubber shoe mounted over the tip where the shoe is either cylindrical or spoon-shaped. U.S. Pat. No. 5,342,283 describes a dental tool having a removable tip comprised of many soft flexible fibers. A knurled surface is used to mate the removable tip to this dental tool. U.S. Pat. Nos. 1,586,302 and 3,869,797 describe dental tools with removable tips mounted on cone-shaped shanks that include additional features such as the ability to carry a medicant or a magnetically activated instrument-carrying member.
U.S. Pat. Nos. 5,100,321 and 5,899,693 describe ultrasonic dental tools with removable tips mounted on cylindrical shafts. In U.S. Pat. No. 5,100,321, the indentation in the tip is round with a 3 degree converging, angle and has a length that is a little less than half the length of the tip. In U.S. Pat. No. 5,899,693 the connecting portion of the tip has an indentation with a diameter slightly smaller than the diameter of the distal shaft and the dimension are selected to maximize the transmission efficiency of the ultrasound energy.
Although dental tools having removable tips are well known, the pliable tips for such dental tools are typically made of a conventional rubber or plastic material. The use of a high-grade silicone material as the working tip for an artist paintbrush has been described in U.S. Pat. No. 5,542,144. In the preferred embodiment described in this patent, the silicone tip is held within a ferrule that is attached to the handle of the brush and a mechanism for expanding the tip against the side wall of the ferrule is used to aid in holding the tip within ferrule. In an alternate embodiment, the possibility of interchangeability of tips is described by using a female threaded ferrule and a male threaded handle. In this embodiment, it is preferred to use barbs or flutes extending from an insert positioned within the end of the tip to secure the tip to the ferrule and prevent the tip from rotating within the ferrule.
Other paint brushes have been developed which use a resilient working tip attached to a handle. In U.S. Pat. No. 2,147,310, a rubber tip is press fit into a ferrule or clamp that is attached to the handle. In U.S. Pat. No. 2,099,030, a spatula-like arrangement for a paint brush is described in which a round core extends from the distal end of the wooden shaft into a cavity in the back of the rubber tip. The cavity in the tip extends less than one-half the length of the tip. In an alternate embodiment, a rectangular shaped stepped extension is used in place of the round core. The purpose of this stepped extension is to create a shoulder that prevents the tip from riding up into the ferrule during operation. The rectangular shape is shown as having a ratio of width to height of 4 to 1. U.S. Pat. No. 4,897,603 describes a paintbrush having a spongy foam tip in the form of an envelope that is held in place on handle by a clamping arrangement. In one embodiment, a flat metal blade member extends into the center of the foam tip in order to provide additional stiffness to the working portion of the foam tip.
While it would be possible to use a paintbrush-like tool for dental applications, most of the working tips for paintbrushes are too large to easily make use of them in dental applications. More importantly, dental tools are preferably sterilized, and the ferrule or clamping arrangements used by these paintbrushes are not well suited for sterilization.
It would be desirable to provide a handheld dental tool having a working tip made of high-grade silicone material. Although existing techniques for attaching a pliable tip to a handheld dental tool could be utilized, the unique characteristics of high-grade silicone material present additional challenges in designing a versatile and functional handheld dental tool that incorporates a silicone tip.